Environmental Engineering Reference
In-Depth Information
groundwater resources; protect air quality by reducing nitrogen emissions (ammonia and NOx
compounds) and the formation of atmospheric particulates; and maintain or improve the physical,
chemical, and biological condition of the soil (NRCS Code 590).
8.4.1.3 Integrated Pest Management (Code 595)
This practice consists of a variety of methods for keeping insects, weeds, disease, and other pests
below economically harmful levels while protecting the soil, water, and air quality. The purposes
of this practice include the prevention or mitigation of off-site pesticide risks to water quality from
leaching, solution runoff, and adsorbed runoff losses; risks to soil, water, air, plants, animals, and
humans from drift and volatilization losses; on-site pesticide risks to pollinators and other beneicial
species through direct contact; and cultural, mechanical, and biological pest suppression risks to
soil, water, air, plants, animals, and humans (NRCS Code 595).
8.4.1.4 Conservation Buffers
Conservation buffers, from simple grassed waterways to riparian areas, provide an additional pro-
tective barrier by capturing potential pollutants that might otherwise move into surface waters. Ten
of the common methods are listed as follows (deinitions and photographs are from NRCS standard
for speciic conservation practice code; Figures 8.12 and 8.13):
•
Alley Cropping (Code 311): Trees or shrubs are planted in sets of single or multiple rows
with agronomic, horticultural crops or forages produced in the alleys between the sets of
woody plants that produce additional products.
•
Contour Buffer Strips (Code 332): Narrow strips of permanent, herbaceous vegetative
cover established around a hill slope, and alternated down the slope with wider cropped
strips that are farmed on the contour.
•
Crosswind Ridges (Code 588): Ridges formed by tillage, planting, or other operations and
aligned across the direction of erosive winds.
•
Field Border (Code 386): A strip of permanent vegetation established at the edge or around
the perimeter of a ield.
•
Filter Strip (Code 393): A strip or area of herbaceous vegetation that removes contaminants
from overland low.
•
Grassed Waterway (Code 412): A shaped or graded channel that is established with suit-
able vegetation to carry surface water at a nonerosive velocity to a stable outlet.
•
Herbaceous Wind Barriers (Code 603): Herbaceous vegetation established in rows or nar-
row strips in a ield across the prevailing wind direction.
•
Riparian Forest Buffer (Code 391): An area of predominantly trees and/or shrubs located
adjacent to and up-gradient from watercourses or waterbodies.
•
Vegetative Barrier (Code 601): Permanent strips of stiff, dense vegetation established along
the general contour of slopes or across concentrated low areas.
•
Windbreak/Shelterbelt Establishment or Renovation (Codes 380 and 650): Windbreaks or
shelterbelts are single or multiple rows of trees or shrubs in linear conigurations.
8.4.1.5 Tailwater Recovery and Reuse System (Code 447)
This is a planned irrigation system in which all the facilities that are utilized in the collection, stor-
age, and transportation of irrigation tailwater and/or rainfall runoff for reuse have been installed
in order to conserve irrigation water supplies and improve off-site water quality (NRCS Practice
Standard).
Here, the tailwater refers to the irrigation water (or stormwater) that runs off the end of an irri-
gated ield. Tailwater systems consist of ditches or pipelines that are used to collect this water and
divert it to a storage location or other system for reuse (Figure 8.14). Tailwater recovery and reuse
systems are applicable to any irrigated agricultural system (typically lood or furrow irrigation) in
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